Picker stick drive mechanism for fly shuttle looms

ABSTRACT

Apparatus for use with weaving looms having fly shuttles to increase efficiency and to reduce noise pollution to a level within guide lines established by the Occupational Safety and Health Administration of the U.S. Government. The apparatus is a combination of elements forming the drive mechanism for the picker sticks which contribute to an overall reduction of noise pollution.

United States Patent Benedict et al.

PICKER STICK DRIVE MECHANISM FOR FLY SHUTTLE LOOMS lnventors: Charles E. Benedict, Tallahassee;

Calvin C. Oliver, Gainesville, both of Fla.

Assignees: Wayne H. Coloney Co., Inc.,

Tallahassee; Controlled Acoustics. Inc., Gainesville, both of Fla.

Filed: Feb. 11, 1974 Appl. No.: 441,705

US. Cl. 139/147; 139/154; 139/157 lnt. C1. D03D 49/26 Field of Search 139/147, 154, 157

References Cited UNITED STATES PATENTS 2/1906 Davis 4. 139/147 111/1921 Johnson :1 139/154 1 1 Aug. 26, 1975 1,592,884 7/1926 Bausingcr H 139/154 2,518,945 8/1951) Sepavich 139/147 2,631,615 4/1951 Ames is 139/147 3,415,289 12/1968 Lacey ct 314..., 139/157 3,527,259 9/1970 Picanol 139/157 3,624,754 11/1971 Tosti H 139/147 Primary Examiner-Mervin Stein Assistant Examiner-Steven Hawkins Attorney, Agent, or FirmA Yates Dowel], Jr.

[57} ABSTRACT Apparatus for use with weaving looms having fly shuttles to increase efficiency and to reduce noise pollution to a level within guide lines established by the Occupational Safety and Health Administration of the US. Government The apparatus is a combination of elements forming the drive mechanism for the picker sticks which contribute to an overall reduction of noise pollution.

9 Claims, 11 Drawing Figures PATENTEU AUBZBIQYS l/I/I/l/I/I/ll FIG. 11

PICKER STICK DRIVE MECHANISM FOR FLY SHUTTLE LOOMS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to apparatus for weaving strands of flexible material into an integral web and relates particularly to fly shuttle type looms used in the weaving of cloth.

2. Description of the Prior Art In the past, wool, cotton and other fibrous naturally occurring materials, as well as synthetic man-made materials such as nylon, dacron, polyester, and the like, have been spun into threads of indeterminate length. A multiplicity of generally parallel threads have been mounted on a loom in a manner to extend from front to rear thereof and provide warp threads. Each of the warp threads passes through a loop or guide on a heddle with such heddles being independently movable so that certain of the heddles can be raised while the remaining heddles are lowered to produce woven patterns in a web of fabric.

After the heddles have been raised and lowered, a shuttle or missile which carries a bobbin of thread, is thrown from one side of the loom to the other between the raised and lowered warp threads while dispensing a filler or weft thread. When the shuttle reaches the end of its travel, the heddles are operated to lower some or all of the upper warp threads and raise some or all of the lower warp threads and the shuttle is thrown back across the loom. The shuttle is supported by a lay having a comb thereon and each time the shuttle is thrown the lay oscillates back and forth of the loom so that the comb heats up or compacts the weft thread to make a tightly woven web of cloth.

In the normal operation of fly shuttle looms, each time the shuttle is thrown from one side of the lay to the other, a pick cycle is completed. Each pick cycle begins when a pick cam mounted on a drive shaft is rotated at a desired speed to operate a pick ball or cam follower Carried by a pick shaft in such a manner that the pick ball follows the contour of the cam. The pick shaft has a pick arm extending outwardly therefrom and such pick arm is swingably connected to one end of a connecting link or pitman. A lug strap is mounted on the opposite end of the connecting link and such lug strap is loosely connected to a picker stick intermediate the ends thereof. The lower end of the picker stick is swingably mounted on a parallel foot mechanism, while the upper end of the picker stick extends upwardly through a slot in the lay and is provided with a pick head which engages one end of the shuttle and slings the shuttle from one side of the lay to the other.

In order to drive the picker stick, the pick cam includes a sharply inclined portion or cam toe, a return portion, and a dwell portion. When the cam toe engages the pick ball, rapid partial rotation of the pick shaft occurs which causes the pick arm to swing inwardly toward the center of the loom and move the connecting link and lug strap. Normally the outer end of the lug strap is spaced slightly from the picker stick so that when the pick arm is swung by the pick shaft, the pitman and the lug strap are relatively freely mov able during the initial motion until the lug strap engages the picker stick with an impact force. Movement of the picker stick in one direction causes rapid acceleration of the shuttle which may or may not be in intimate engagement with the pick head. If the pick head and shuttle are slightly separated, additional noise is created when the pick head slaps the shuttle. While the picker stick is moving inwardly and outwardly of the lay slot, the lay is moving back and forth in a direction generally normal to the movement of such picker stick. The double movement of the picker stick and the lay causes the picker stick to fram around or chatter within the lay slot which not only creates a slapping noise but also sets up acoustic vibrations in the picker stick.

When the pick ball reaches the point of inflection or point of circle tangency adjacent to the top of the cam toe profile, the shuttle leaves the pick head and the pick arm, pitman, lug strap, and picker stick begin to decelerate. However, since the picker stick normally is freely floating within the lug strap, such picker stick continues its movement and slaps one or more check straps mounted on the lay before it hits a bumper mounted at the end of the lay slot. As the pick ball reaches the point of inflection of the cam, the momentum of the pick ball causes such pick ball to be thrown clear of the surface of the cam until a resilient member on the parallel foot mechanism moves the picker stick outwardly and the picker stick engages the end of the lug strap which in turn exerts a pull on the pitman and causes the pick arm to rotate the pick shaft in a direction to cause the pick ball to return to the surface of the cam. The return of the pick ball to the cam surface under resilient pressure causes substantial impact which frequently causes the pick ball to bounce and then strike the cam again. Each impact between the cam and the pick ball creates substantial noise.

The noise created by a single loom during each pick cycle is defiled by a series of high frequency noise peaks of short duration and such peaks are only slightly higher than the permissible levels. However, when a plurality of looms are operating in a weaving room, peak noises of one loom reinforce and accentuate the peak noises of other looms so that the resulting noise level is substantially above the permissible limits.

Some examples of prior art structures are the US. Pat. Nos. to Loud 437,215; Begins 628,914; Walmsley et al. 784,195; Harmon et al. 1,215,271; Anderson 1,790,966; Ladeau 1,716,178; Burton 2,045,978; Norris et a]. 2,419,486; Muller 2,440,181; Moe 2,445,744; Vanore 2,466,287; Norris 2,600,019; Schwabe 2,601,874 and Lacey et al. 3,415,290.

SUMMARY OF THE INVENTION The present invention is a picker stick drive mechanism for fly shuttle looms in which most of the component parts have been redesigned or otherwise modified in a manner to retain substantially conventional shapes while providing for noise reduction so that the combined noise level of a plurality of looms within a weaving room at least approaches acceptable levels. This is done by:

1. Redesigning the pick cam profile.

2. Providing sound absorbing cushioning material on at least portions of the cam, lug strap, picker stick, and lay slot.

3. Eliminating relative movement between the picker stick and the lug strap.

4. Substantially retaining the pick ball in intimate en gagement with the pick cam.

5. Substantially reducing or eliminating acoustic vibration of the elongated picker stick.

6. Substantially reducing or eliminating chatter between the picker stick and the lay slot.

7. Arranging the elements in cooperating relationship with each other in such a manner that the shuttle remains in engagement with the pick head.

8. Controlling the dynamic sequencing of the elements in such a way that free-flight and transient behavior noise is reduced or eliminated.

It is an object of the invention to reduce the noise pollution inherent in fly shuttle weaving looms to a level acceptable to the Occupational Safety and Health Administration of the US. Government.

Another object of the invention is to increase the efficiency of fly shuttle looms through dynamic sequencing and by eliminating waste motions so that a greater number of picks per minute can be made to increase the amount of material which can be woven within a specified time period as well as to reduce nonproductive time while the looms are being repaired.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective illustrating the picker stick and drive mechanism therefor.

FIG. 2 is an enlarged plan view of the pick cam on the line 2-2 of FIG. 1.

FIG. 3 is an enlarged section on the line 33 of FIG. 2..

FIG. 4 is an enlarged section on the line 4-4 of FIG. 1.

FIG. 5 is a section on the line 55 of FIG. 4. FIG. 6 is a fragmentary section similar to FIG. 5 and illustrating a modified lug strap.

FIG. 7 is a side elevation of a picker stick per se.

FIG. 8 is an enlarged section on the line 8-8 of FIG. 7.

FIG. 9 is a section similar to FIG. 8 illustrating a modified form of the invention.

FIG. 10 is an enlarged fragmentary section on the line 10-10 of FIG. 1.

FIG. 11 is a section on the line 1111 of FIG. 10.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With continued reference to the drawings, a fly shuttle loom 15 is provided having a lay 16 which is moved back and forth in the direction of the arrow 17 in timed relationship by conventional loom mechanism (not shown). At each end of the lay 16 a binder l8 and a shuttle box 19 are provided which are slightly movable toward and from each other to frictionally engage and arrest the shuttle 20 as such shuttle is thrown from end to end of the lay. A lay slot 21 extends vertically through each end of the lay 16 through which the upper end of an elongated picker stick 22 extends. A pick head 23 is mounted on the upper end of the picker stick above the lay 16 and such pick head is provided with a conical recess 24 for receiving the spur or tip of the shuttle 20.

The lower end of the picker stick 22 is mounted on a parallel foot mechanism 25 having a mounting bracket 26 connected to the picker stick and being swingably mounted by pivots 27 to a body 28. The body 28 is provided with a resilient member or spring 29 which is connected to the lower end of the picker stick 22 t0 normally urge the upper portion of the picker stick outwardly of the lay slot 21. The body 28 is mounted on a shaft 30 which is swingably supported by bearings (not shown) carried by the frame of the loom 15 in a manner to permit the parallel foot mechanism 25 and the picker stick 22 to swing back and forth with the lay 16.

In order to drive the picker stick to cause the shuttle to be thrown from side to side of the lay, a drive shaft 34 is driven in the direction of the arrow 35 in any desired manner such as an electric motor or the like (not shown) in timed relationship with the loom mechanism which moves the lay back and forth. A cam 36 is adjustably fixed to the drive shaft 34 and such cam includes a toe portion 37, return portion 38 and a dwell portion 39. In a normal loom cam the toe portion is designed geometrically using circles of fixed radii and these circles are tangent to each other at certain points around the perimeter of the cam. The toe portion normally has occupied approximately 19 of rotation of the cam with approximately 17 utilized to accelerate the picker stick and shuttle and the remaining 2 utilized to decelerate the picker stick after the shuttle has been thrown toward the other end of the lay. Because of this type of design, the first and second time derivatives of the displacement or surface profile are discontinuous at the points where the circles become tangent to each other which creates inflection points that are the equivalent of impact. This prior art structure is illustrated in phan tom lines in FIG. 2.

In the present invention the upwardly inclined portion of the cam toe has been redesigned so that the curvature does not have a fixed radius but instead is provided with continuous derivatives on shifting centers to smooth out the inflection points and reduce or eliminate jerk or shock. The toe curvature causes acceleration of the picker stick and shuttle within approximately 12 of rotation of the cam and approximately 7 of rotation are utilized to decelerate the picker stick as shown in full lines in FIG. 2. Substantially the entire surface area of the return portion 38 and the dwell portion 39 of the cam have been covered by a vibration absorbing and dampening pad 40 for a purpose to be described later.

A pick ball or cam follower 41 is rotatably mounted on an axle 42 carried by a pick shaft 43 and such shaft is mounted for partial rotation in bearings 44 supported by the frame of the loom. The pick ball rotatably engages the outer periphery of the cam 36 so that the cam causes the pick shaft to partially rotate about a fixed axis. A pick arm 45 is connected at one end to the pick shaft 43 and extends downwardly therefrom. As illustrated, the pick arm includes a pair of spaced generally parallel lugs; however, it is contemplated that such pick arm could be a unitary body having a bifurcated lower end. The lower end of the pick arm is connected by a pivot 46 to a connecting link or pitman 47 which may be constructed as a one-piece member or, as illustrated in FIGS. 1 and 4, such connecting link may include an inner member 48 having a ball 49 at one end universally connected to a socket 50 carried by an outer member 51. The lower end of the pick arm 45 also is connected by a spring or other resilient member 52 to the parallel foot mechanism 25 or the frame of the loom to exert a force which causes the pick ball 41 to remain substantially in rolling engagement with the periphery of the cam 36.

The end of the connecting link remote from the pick arm 45 is adjustably connected to a lug strap 55 in any desired manner as by one or more fasteners 56. With particular reference to FIGS. 4 and 5, the lug strap 55 is generally U-shaped in cross-section and includes a pair of generally parallel arms 57 connected at their outer ends by an end wall 58. To adjustably connect the lug strap 55 to the connecting link 47, each of the arms 57 is provided with an elongated slot 59 through which the fastener 56 extends.

The picker stick 22 extends upwardly through the lug strap 55 and is connected thereto so that movement of the connecting link 47 in the direction of the arrow 60 causes the picker stick to swing about the pivots 27 of the parallel foot mechanism. As illustrated best in FIGS. 4 and 5, the lug strap 55 is connected by a pin or other fastener 61 to a power block 62 which is adjustably mounted lengthwise of the picker stick by one or more clamps 63. The power block 62 is adjustable lengthwise of the picker stick to adjust the throw or power stroke of the picker stick as well as the acceleration thereof.

Since the lay 16 is moving the picker stick in a back and forth direction relative to the loom at the same time that the drive mechanism is moving the picker stick in and out relative to the loom, it is desirable to prevent the sides of the picker stick from striking or slapping the sides of the arms 57 of the lug strap 55 and thereby eliminate any impact related noise. As illustrated in FIG. 5, a pair of resilient leaf springs 64 are provided in which the opposite ends of each of the springs engage the inner surfaces of the lug strap arms 57 while the central portion of each of the springs is bowed inwardly of the lug strap into frictional engagement with the sides of the picker stick 22. Each of the leaf springs 64 has an opening 65 to accommodate the pin 61 by which the lug strap is connected to the power block 62. Lateral movement of the picker stick 22 within the lug strap causes the spring 64 to flex and absorb such movement and may cause slight rotation of the outer member 51 of the connecting link about the ball and socket connection with the inner member 48.

With particular reference to FIG. 6, the lug strap 55 can be connected directly to the picker stick 22 by a pin or fastener 66 which is fixed to the arms 57 and extends through an opening 67 in the picker stick 22. If desired a plurality of vertically spaced openings can be provided along the length of the picker stick to provide for adjustability of the lug strap along the length of the picker stick. To prevent contact between the picker stick and the arms of the lug strap, a resilient member 68 such as a coil spring or the like is disposed about the pin 66 on each side of the picker stick to resist relative movement between the picker stick and the lug strap. It is contemplated that the resilient members 68 could be replaced by either resilient or rigid spacers which prevent contact between the picker stick and the lug strap 55.

With particular reference to FIGS. 7 and 8, picker sticks of conventional fly shuttle looms are generally made of very hard wood or metal so that they can withstand the impacts associated with their operation in the loom. Due to the material used, these picker sticks are excellent vibration and sound transmitters so that when the picker sticks engage either the ends or the sides of the lay slot, or engage the ends or sides of the lug strap during the operation of the loom substantial impact related vibrations have occurred particularly along the broad sides of the picker stick.

In order to dampen out or prevent these vibrations, the upper side portions of the picker stick 22 have been provided with a covering of vibration cushioning and absorbing material 71 and the lower side portions have been provided with a covering of vibration cushioning and absorbing material 72. The area between the upper and lower covers defines the location of the lug strap so that the strength of the picker stick in the area of the lug strap is not impaired. As noted previously, the lug strap is provided with leaf spring 64 and other resilient members 68 to prevent contact between the lug strap and the sides of the picker stick. The covers 71 and 72 may be bonded to the sides of a conventional picker stick or, if desired, portions of the picker stick may be removed to accommodate the covering material so that the external surface of the covers is substantially flush with the remainder of the picker stick.

With particular reference to FIG. 9, another embodiment of the picker stick is provided in which a cushioning and vibration absorbing cover 73 is applied to both sides and both ends of the picker stick and the upper and lower portions thereof. The vibration absorbing cover 73 on the ends of the picker stick dampens out any vibrations caused by impact between the ends of the picker stick and some other structure, such as the ends of the lay slot 21. Also if desired the picker stick 22 may be constructed of several laminations each of which has a length and width the same as the picker stick disclosed in FIGS. 1 and 7 but having a reduced thickness so that several laminae are bonded together to produce a picker stick of conventional thickness. In this construction the wooden or metallic laminations 74 are separated by a vibration cushioning and absorbing lamination 75 which provides an impedance mismatch to prevent vibrations from passing through the picker stick.

In some looms the picker stick frams around or chatters within the lay slot an excessive amount which causes sound vibrations in both the picker stick and the lay. Supplying the picker stick with cushioning and absorbing material as previously described has assisted in alleviating this problem by reducing vibrations within the picker stick. As illustrated best in FIGS. 10 and 11, a pad 76 of vibration cushioning and absorbing material is provided along each side of the lay slot to dampen out the impact related vibrations and prevent such vibrations from being transmitted to the lay 16.

In the operation of the device, the cam 36 is driven in the direction of the arrow 35 so that when the pick ball 41 engages the toe portion 37 of the cam, the pick shaft 43 is partially rotated rapidly about its axis by the pick ball. Rotation of the shaft 43 causes the pick arm 45 to swing toward the center of the loom and rapidly moves the connecting link 47 inwardly. Since the lug straap 55 on the outer end of the connecting link is positively connected to the picker stick 22, as soon as the pick shaft 43 begins its partial rotation, the picker stick swings about the pivots 27 on the parallel foot mechanism. The shuttle 20 which is in engagement with the pick head 23 is accelerated rapidly and is thrown across the lay 16. The shuttle leaves the pick head at approximately the same time that the ball 41 reaches the end of the accelerating section of the toe portion 37 of the cam and the pick ball begins to decelerate in its final upward movement. The resilient member 52 immediately begins to move the pick shaft 43 in a reverse direction so that the pick ball 41 remains in substantially intimate engagement with the outer periphery of the return portion 38 of the cam 36. The vibration absorbing pad 40 along the periphery of the cam damps out noise vibration caused by relative movement between the cam and the pick ball.

As the cam 36 continues to rotate, the resilient member 52 and the spring 29 continue to rotate the pick shaft 43 so that the connecting link 47, lug strap 55 and spring 29 return the piq er stick 22 toward the outer end of the lay slot 21. At approximately the time that the pick ball 41 reaches the dwell portion 39 of the cam, the cam on the opposite side of the loom throws the shuttle back across the lay where the binder l8 and shuttle box 19 engage the same and cause rapid deceleration. As the shuttle passes between the binder and the shuttle box, the spur of the shuttle engages the recess 24 of the pick head so that the pick head stops outward movement of the shuttle.

The engagement of the pick head by the shuttle normally transmits a shock through the picker stick, lug strap, connecting link, pick arm, and pick ball to the cam 36 to cause the pick ball to bounce on the cam, however, the pad 40 on the periphery of the cam absorbs both the impact shock and the vibrations so that no bounce occurs.

Normally fly shuttle looms have produced approximately three pick cycles per second or approximately 178 cycles per minute by accelerating the shuttle to a velocity of approximately 525 inches per second. The improved cam toe profile, which accelerates the shuttle in a shorter period of time, has permitted approximately 188 to 190 picks per minute to provide an increase in the weaving capacity of the loom while substantially reducing the noise emanating therefrom.

We claim:

1. Apparatus for throwing the shuttle of a fly shuttle loom from end to end of a lay movably mounted on a loom frame, the apparatus comprising a cam having a toe portion and at least a second portion, vibration absorbing pad means mounted on the periphery of at least part of the second portion of said cam, a pick ball carried by a pick shaft and engageable with said toe portion and said pad means of said cam, a pick arm mounted on said pick shaft in spaced relationship to said pick ball, connecting link means swingably connected to said pick arm, lug strap means carried by said connecting link means, a picker stick swingably mounted at one end on the loom in a manner to permit the picker stick to move in and out as well as back and forth relative thereto, an intermediate portion of said picker stick being received within said lug strap means, the upper end of said picker stick extending through an elongated slot in the loom lay and having a pick head selectively engageable with the shuttle of the loom, and resilient means connecting the fixed frame of said loom to said pick shaft in a manner to urge said pick ball into intimate engagement with said cam, whereby when the cam is driven the toe portion causes the picker stick to throw the shuttle from one end of the lay to the other and said pad means absorbs the noise and shock vibrations caused by contact between the second portion of said cam and said pick ball.

2. The structure of claim 1 including means carried by said lug strap to prevent direct engagement between the sides of said lug strap and said picker stick when said picker stick is moved back and forth.

3. The structure of claim 1 in which said picker stick includes vibration absorbing cover means disposed on at least portions of the opposite sides thereof.

4. The structure of claim 3 in which said cover means surrounds at least portions of said picker stick.

5. The structure of claim 1 including power block means adjustably mounted on said picker stick, and means connecting said power block means to said lug strap.

6. The structure of claim 1 including pin means connecting said intermediate portion of said picker stick to said lug strap means.

7. in a fly shuttle loom having a frame, a lay mounted on said frame for back and forth movement, a shuttle adapted to be thrown from end to end of said lay, binder means at each end of said lay for catching the shuttle, a picker stick located adjacent to each end of said lay, and means for swingably mounting one end of each picker stick on said frame, the improvement comprising apparatus for driving each of said picker sticks including a cam having first and second peripheral portions, said first portion having an upwardly inclined surface with a curvature formed of continuous derivatives on shifting centers, a vibration absorbing pad means mounted on the periphery of said second portion, a pick shaft mounted on said frame in spaced relationship to said cam, a pick ball carried by said pick shaft and engageable with the periphery of said cam to cause partial rotation of said shaft about a fixed axis, a pick arm mounted on said pick shaft, and link means connecting said pick arm to an intermediate portion of said picker stick, whereby rotation of said cam causes the first portion thereof to partially rotate said shaft so that the picker stick throws the shuttle across the loom with a minimum of noise and said pad means on the second portion of said cam reduces the noise between said cam and said pick ball.

8. The structure of claim 7 including resilient means urging said pick ball into engagement with said cam.

9. The structure of claim 7 in which said link means includes a generally U-shaped lug strap receiving said picker stick, and means carried by said lug strap to prevent contact between the sides of the picker stick and the sides of said lug strap. 

1. Apparatus for throwing the shuttle of a fly shuttle loom from end to end of a lay movably mounted on a loom frame, the apparatus comprising a cam having a toe portion and at least a second portion, vibration absorbing pad means mounted on the periphery of at least part of the second portion of said cam, a pick ball carried by a pick shaft and engageable with said toe portion and said pad means of said cam, a pick arm mounTed on said pick shaft in spaced relationship to said pick ball, connecting link means swingably connected to said pick arm, lug strap means carried by said connecting link means, a picker stick swingably mounted at one end on the loom in a manner to permit the picker stick to move in and out as well as back and forth relative thereto, an intermediate portion of said picker stick being received within said lug strap means, the upper end of said picker stick extending through an elongated slot in the loom lay and having a pick head selectively engageable with the shuttle of the loom, and resilient means connecting the fixed frame of said loom to said pick shaft in a manner to urge said pick ball into intimate engagement with said cam, whereby when the cam is driven the toe portion causes the picker stick to throw the shuttle from one end of the lay to the other and said pad means absorbs the noise and shock vibrations caused by contact between the second portion of said cam and said pick ball.
 2. The structure of claim 1 including means carried by said lug strap to prevent direct engagement between the sides of said lug strap and said picker stick when said picker stick is moved back and forth.
 3. The structure of claim 1 in which said picker stick includes vibration absorbing cover means disposed on at least portions of the opposite sides thereof.
 4. The structure of claim 3 in which said cover means surrounds at least portions of said picker stick.
 5. The structure of claim 1 including power block means adjustably mounted on said picker stick, and means connecting said power block means to said lug strap.
 6. The structure of claim 1 including pin means connecting said intermediate portion of said picker stick to said lug strap means.
 7. In a fly shuttle loom having a frame, a lay mounted on said frame for back and forth movement, a shuttle adapted to be thrown from end to end of said lay, binder means at each end of said lay for catching the shuttle, a picker stick located adjacent to each end of said lay, and means for swingably mounting one end of each picker stick on said frame, the improvement comprising apparatus for driving each of said picker sticks including a cam having first and second peripheral portions, said first portion having an upwardly inclined surface with a curvature formed of continuous derivatives on shifting centers, a vibration absorbing pad means mounted on the periphery of said second portion, a pick shaft mounted on said frame in spaced relationship to said cam, a pick ball carried by said pick shaft and engageable with the periphery of said cam to cause partial rotation of said shaft about a fixed axis, a pick arm mounted on said pick shaft, and link means connecting said pick arm to an intermediate portion of said picker stick, whereby rotation of said cam causes the first portion thereof to partially rotate said shaft so that the picker stick throws the shuttle across the loom with a minimum of noise and said pad means on the second portion of said cam reduces the noise between said cam and said pick ball.
 8. The structure of claim 7 including resilient means urging said pick ball into engagement with said cam.
 9. The structure of claim 7 in which said link means includes a generally U-shaped lug strap receiving said picker stick, and means carried by said lug strap to prevent contact between the sides of the picker stick and the sides of said lug strap. 